John, rice vinegars are made from fermented rice. Rice wine vinegars are generally made from the lees of the wine or sake. There are many types of each vinegar, with generally subtle differences in taste.

Don't know for sure, but the normal progression is for sugars (broken down starches in the case of rice) to ferment in the presence of water and yeast to produce alcohol. The alcohol solution is then turned into vinegar in the presence of vinegar bacteria (aceter bacter?). So I would think they are the same thing.

Right, Howie. They just allude to the differences between the two basic types, and from what I've read, so do the Japanese. I'll see if I can find a clearer reference -- I remember getting intrigued with the various vinegars several years ago -- Rosengarten may be my source.

I'll revert if I can find the reference -- I'm certainly not an expert.